Links using non-HTTP schemes opened from other apps such as Safari could have allowed spoofing of website addresses

published 2025-05-21 17 mo ago modified 2026-10-05 34 d ago also EUVD-2025-16036

cvss: 4.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits: 0; none known

Opening maliciously-crafted URLs in Firefox from other apps such as Safari could have allowed attackers to spoof website addresses if the URLs utilized non-HTTP schemes used internally by the Firefox iOS client. This vulnerability was fixed in Firefox for iOS 139.

Patch / fix

fixed in 1

mozilla firefox 139

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 17 mo ago (2025-05-21)

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
CNA	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

Affected products

Mozilla Firefox for iOS

Classification

Weakness

CWE-939 Improper Authorization in Handler for Custom URL Scheme

References

mozilla.org /security/advisories/mfsa2025-39/
vendor-advisory
bugzilla.mozilla.org /show_bug.cgi?id=1951558
permissions-required

Sources

CVE List CVE-2025-5020
NVD CVE-2025-5020

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CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary